Gravity Single Relay Module

Worked great with DFRobot Mega IO Expansion Shield. Connected up to 6 relays and worked with solely usb power to the Mega.

I like this relay because it can be used with 5V and 3.3V Arduino and similar microcontrollers. There is also a NC contact in addition to the normally open so the relay contacts act like a SPDT switch. The contacts can handle 10A. High signal from the microprocessor turns on the relay (green wire). Red wire is for + power, black wire for - power. Here is what DF Robot says about it: It is specially designed for low-voltage devices and works well under 3.3V power supplies, just like the Raspberry Pi relay board. In addition, the module has a wide range of power inputs. In our tests, once it reaches 2.8~5.5V, it can also support 1.8V devices. DFRobot’s Digital Relay Module uses a high quality 3V relay. It can handle up to 10A current and mechanical parts are guaranteed up to 100 million uses. An on-board indicator LED demonstrates the relay’s state. Terminals include normally open (NO) and normally closed (NC). The module uses a Gravity-3 pin interface, which requires no soldering for convenient plug and play usage. Introducing the Gravity Digital Relay Module – the latest addition to DFRobot’s Gravity series! This module is a little different to the other relays in our store - not only is it compatible with 5V Arduino boards, but also with Raspberry Pi, BBB (BeagleBoard Black), mbed, Intel Joule, Arduino 101 and other 3.3V devices. Operating Voltage: 2.8V ~ 5.5V Input Signal: High Level (≥2.8V); Low Level (≤0.5V) Max Switching Current: 10A

It's a good product for any application you may have. This relay is easy to wire and understand, so anyone can switch between two different voltage supply.